On 17/Oct/10 8:02 AM, Michael Snoyman wrote:
In the gist you sent, the problem is that you are reading the HTTP response as a String. The HTTP library doesn't deal well with non-Latin characters when doing String requests; you should be using ByteString and then converting. It's a little tedious using the HTTP library with ByteStrings, which is one of the reasons I wrote http-enumerator. Here's some working code. The main point is to convert the UTF8 octets to a String.
You could also consider using one of the JSON libraries that support bytestrings directly instead of strings, which will likely result in much better performance. Contenders include JSONb[1] and yajl-enumerator[2].
import Network.HTTP.Enumerator import qualified Text.JSON as JSON import qualified Data.ByteString.Lazy.UTF8 as BSLU
data GithubUser = GithubUser { name :: String, location :: String } deriving (Eq, Show)
instance JSON.JSON GithubUser where readJSON (JSON.JSObject object) = let (Just a) = lookupM "user" $ JSON.fromJSObject object (JSON.JSObject b) = a user = JSON.fromJSObject b in do name<- lookupM "name" user>>= JSON.readJSON location<- lookupM "location" user>>= JSON.readJSON return $ GithubUser { name = name, location = location }
showJSON user = JSON.makeObj [ ("name", JSON.showJSON $ name user), ("location", JSON.showJSON $ location user) ]
lookupM :: (Monad m) => String -> [(String, a)] -> m a lookupM x xs = maybe (fail $ "No such element: " ++ x) return (lookup x xs)
main = do jsonLbs<- simpleHttp "http://github.com/api/v2/json/user/show/igstan" let jsonText = BSLU.toString jsonLbs let result = JSON.decode jsonText :: JSON.Result GithubUser showResult result where showResult (JSON.Ok json) = putStrLn $ name json showResult (JSON.Error e) = putStrLn e
Michael
[1] http://hackage.haskell.org/package/JSONb-1.0.2 [2] http://hackage.haskell.org/package/yajl-enumerator
Thanks Michael, now it works indeed. But I don't understand, is there any inherent problem with Haskell's built-in String? Should one choose ByteString when dealing with Unicode stuff? Or, is there any resource that describes in one place all the problems Haskell has with Unicode? -- Ionuț G. Stan | http://igstan.ro